Tom Joad: the main character of the play, although not always on the right side of the law he is the symbol for justice. However, when Tom tries to help Reverend Jim Casy and ends up losing control and killing one of the other 'strikebreakers', he proves more of a hindrance that a help. His fatal flaw lies in his inability to keep his temper.
Ma Joad: the mother of Tom, Noah, Rose of Sharon, Ruthie and Winfield. She is a very strong character in the play and admirably becomes accustomed to the poverty and starvation of her situation. She is the epitome of the American Spirit for her generation and it is her defiance that keeps the family together for so long. Her only flaw was maybe giving too much, constantly sharing with others and allowing Jim Casy to join their trip.
Pa Joad: the head of the Joad Family but not the authority. He feels inadequate because he cannot provide for the family.
Rose of Sharon: Tom Joad's pregnant younger sister married to Connie Rivers. Rose of Sharon is the one adult who retains a sense of optimism for the future. She dreams of a middle-class life with her husband and child, but becomes paranoid and disillusioned once her husband abandons her when they reach California.
Connie Rivers: the shiftless husband of Rose of Sharon. He dreams of taking correspondence courses to provide him with job opportunities and the possibility of a better life. When he reaches California and does not find work, immediately becomes disillusioned and abandons his pregnant wife.
Noah Joad: Tom's older brother who is slightly disabled as a result of problems during his birth. He leaves the family to remain an outsider from society, supporting himself by catching fish from the nearby river.
Al Joad: Tom's younger brother who is sixteen years old. He is concerned with cars and girls, and remains combative and truculent toward the rest of the family. Out of all the Joads, he has the most knowledge of cars, and fears that the rest of the family will blame him if anything goes wrong. He dreams of becoming a mechanic, and becomes engaged to Aggie Wainwright by the end of the novel.
Ruthie Joad: one of the two small children in the Joad family, it is Ruthie who reveals that Tom is responsible for the murder at Hooper Ranch, forcing him to leave his family to escape the police.
Winfield Joad: the other small child in the Joad family, Winfield becomes severely ill during the course of the novel from deprivation, but survives his illness.
Grandpa Joad: an energetic, feisty old man, Grandpa refuses to leave Oklahoma with the rest of his family, but is forcibly taken on the journey after the other family members drug him. Soon afterward, unable to face leaving his home, Grandpa dies of a stroke.
Grandma Joad: Grandma Joad does not survive much longer than her husband. She becomes severely ill on the journey to California and dies not long after they reach the state.
Reverend Jim Casy: a fallen preacher who too often succumbed to temptation, Casy left the ministry when he realized that he did not believe in absolute ideas of sin. He espouses the idea that all that is holy comes from collective society, a belief that he places in practical context when, after time in jail, he becomes involved with labor activists. Casy is a martyr for his beliefs, murdered in a confrontation with police.
The Mayor of Hooverville: a half-crazed old migrant worker. He is ‘bull-simple' from continued beatings by the California police.
Floyd Knowles: he befriends Al Joad and tells the Joad family about work opportunities and about the government camp at Weed patch.
Elizabeth Sandry: a fundamentalist zealot who complains about the alleged sin taking place at the government camp, including dancing, and frightens Rose of Sharon with her admonitions about sin.
Aggie Wainwright: the young woman to whom Al Joad becomes engaged.